I am no expert on QRO but I am in the process of building the 3CX1500D7 amp
in the 2006 handbook. I am as interested in the engineering aspects of QRO as in the engineering aspects of QRP. The economics of my project are getting a little out of hand so I visited the Alpha Booth at Dayton to see what they have done with their new amp, the 9500 and was very impressed. I almost lost my mind and gave them a deposit. Sanity prevailed. Then I remembered that Elecraft was doing an amplifier and walked 50 feet to their booth. I spoke with Eric for a while about the amplifiers (800 watt and 1500 watt versions). I was totally impressed with the design and would have given Eric a deposit if he had been taking them (I settled on a KX1 at the other end of the power spectrum). The big amp uses 16 FET's (not Motorola but I can't remember which ones) and auto senses transceiver frequency. An auto tuner is included, I think. The pricing is about 5/8ths or 5/9ths of the big Alpha. The pricing is sufficiently low and the features sufficiently high that I will have to seriously consider abandoning my project in favor of the Elecraft Amp. Of course, then I will lose out on the engineering and building experience. Oh, the Elecraft amps can be purchased assembled or in kit form. Kit form reduces the price 400 dollars or so. Ed Lambert, P.E. KD3Y K2/1999 KX1/1492 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
On 5/22/06, Ed Lambert <[hidden email]> wrote:
> I am no expert on QRO but I am in the process of building the 3CX1500D7 amp > in the 2006 handbook. I am as interested in the engineering aspects of QRO > as in the engineering aspects of QRP. > > The economics of my project are getting a little out of hand so I visited I'm curious, what makes RF amplifiers fairly expensive projects? I admit I have no experience or exposure to them, but as far as I can tell the two major building blocks are a power supply and a not terribly complex amplifier circuit. Is the bulk of the cost in the amp device(s) - power transistors or vacuum tubes/values? Thanks. -Michael VE3TIX _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
The reasons amps seem expensive:
1) They use expensive parts if bought new. Manufacturers can't/won't/don't use surplus, so they have to pay full price for everything. 2) Many of the parts are expensive because they're custom and/or low quantity items. 3) The market is relatively limited, so the engineering and tooling costs have to be amortized over fewer units. Elecraft has sold less than 6000 K2s since the rig was introduced in 1999. As good as the Elecraft amps obviously are, and as much as many of us want one, how many units can they reasonably expect to sell in the next 7 years? 73 de Jim, N2EY -----Original Message----- From: michael taylor <[hidden email]> To: [hidden email] Sent: Mon, 22 May 2006 11:23:57 -0400 Subject: Re: [Elecraft] QRO I'm curious, what makes RF amplifiers fairly expensive projects? I admit I have no experience or exposure to them, but as far as I can tell the two major building blocks are a power supply and a not terribly complex amplifier circuit. Is the bulk of the cost in the amp device(s) - power transistors or vacuum tubes/values? _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by michael taylor-3
For me it is the cost of the tube ~$600, the enclosures (I was planning to
purchase new) ~$300 -$400, power supply transformer ~$500 - $600, power supply capacitor ~$400 -$500, vacuum variable capacitors several hundred dollars, etc. I was planning to purchase all new; considerable savings by looking around. I wanted to go first class, but maybe won't be able to do it. My total cost for all new stuff would be several (4 or 5) thousands of dollars. And since I was going to revise the handbook design, there would be no assurance of total success. Ed Lambert, KD3Y > > I'm curious, what makes RF amplifiers fairly expensive projects? I > admit I have no experience or exposure to them, but as far as I can > tell the two major building blocks are a power supply and a not > terribly complex amplifier circuit. > > Is the bulk of the cost in the amp device(s) - power transistors or > vacuum tubes/values? > > Thanks. > > -Michael > VE3TIX > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by michael taylor-3
michael taylor wrote:
> I'm curious, what makes RF amplifiers fairly expensive projects? Tube amplifiers are expensive because high power components (HV variable capacitors, high power bandswitches, power transformers, tubes, sockets, etc.) are expensive. In addition, although the basic circuit is quite simple, ancillary circuits to protect the expensive parts and provide functionality like QSK and automatic tuning are needed. Finally, the enclosure is large and must be well-constructed to be RF tight. A homebrewer can build an amplifier relatively cheaply by using surplus Russian tubes and scrounging parts. But you need to know what you're doing, since mistakes can be fatal. Transistor amplifiers are expensive because they are more complex. A KW amplifier may have 8 power transistors, and the protective circuitry may be more complicated than that for a tube amplifier. If you know that you will be driving a 50 ohm load, automatic tuning is simple; just switch in the appropriate lowpass filter for each band. However, transistor amps are unhappy with even a low-to-moderate SWR, so a built-in antenna tuner is really needed. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
I have always wanted to try building one of those big amplifiers. One thing
that stops me is that I have no idea where you get or how you build all the "sheet metal" parts --- complicated pieces of chassis, etc. Anybody out there who knows how people manage to build or source these? Thanks. 73 de Brian W3BW -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Vic K2VCO Sent: Monday, May 22, 2006 12:40 To: michael taylor Cc: [hidden email] Subject: Re: [Elecraft] QRO michael taylor wrote: > I'm curious, what makes RF amplifiers fairly expensive projects? Tube amplifiers are expensive because high power components (HV variable capacitors, high power bandswitches, power transformers, tubes, sockets, etc.) are expensive. In addition, although the basic circuit is quite simple, ancillary circuits to protect the expensive parts and provide functionality like QSK and automatic tuning are needed. Finally, the enclosure is large and must be well-constructed to be RF tight. A homebrewer can build an amplifier relatively cheaply by using surplus Russian tubes and scrounging parts. But you need to know what you're doing, since mistakes can be fatal. Transistor amplifiers are expensive because they are more complex. A KW amplifier may have 8 power transistors, and the protective circuitry may be more complicated than that for a tube amplifier. If you know that you will be driving a 50 ohm load, automatic tuning is simple; just switch in the appropriate lowpass filter for each band. However, transistor amps are unhappy with even a low-to-moderate SWR, so a built-in antenna tuner is really needed. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Brian,
In the past, there were 3 basic options; I suspect they are the same today: 1. Buy a standard sized box to use as the chassis; use a drill press to drill small screw holes after your layout is determined and inked in the box. Use a chassis punch set to cut the larger holes, and so on. Buy other pieces of metal and cut to fit. 2. complete a drawing package and take to a small metal working shop that has a metal brake to bend sheet metal, and the the parts formed for you from sheet metal you provide or buy from them; I like to us 6061T6 my self, because it is easy to machine, form, and weld if needed. 3. Get a small metal brake, shear and drill press and do it all yourself. It can be the cheapest solution if you find you made an error in your drawings, want to add something, do another project, and so on. 4. You may want to make an exact copy of a handbook amplifier the first time out of the gate, to get this part of the process under control, and that may even yield a source of drawings for you, making (2) or (3) easier for you. It can be a very fun part of the process as well; there are many tricks you can use to detour around the stuff you don't have; for example, if you don't have a brake to bend those nice curved corners, you can cut all the parts with a shear, and use right angle stock along the inside edges; counter sink the screw holes on the outside, and you get a very presentable cabinet as well. These methods of getting the sheet metal work done have served me well for five decades, and I am sure others can provide refinements and additional suggestions. 73 de Dave, W5SV Brian F. Wruble wrote: > I have always wanted to try building one of those big amplifiers. One thing >that stops me is that I have no idea where you get or how you build all the >"sheet metal" parts --- complicated pieces of chassis, etc. Anybody out >there who knows how people manage to build or source these? > > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by Brian Wruble
Brian F. Wruble wrote:
> I have always wanted to try building one of those big amplifiers. One thing > that stops me is that I have no idea where you get or how you build all the > "sheet metal" parts --- complicated pieces of chassis, etc. Anybody out > there who knows how people manage to build or source these? You can purchase commercial aluminum chassis and rack panels. The shielding enclosure can be made of aluminum angle and sheet stock available at a hardware store. You will need a good vise, a hacksaw and a collection of files. Although you can drill holes with a handheld drill, a drill press makes it much easier to do a good job. There are many sources of prefabricated chassis components available on the net. For one example, look at <http://home.flash.net/~k3iwk/>. For examples of good homebrew construction, look at old ARRL Handbooks. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by N2EY
Hi Jim, et al:
Oh, I suspect they'll sell MANY amps... and NOT just to Elecraft owners. The mere fact that the KPA800/1500 is NOT specific to the Elecraft line of products, means that it'll work with just about ANY current-production transceiver, and will many older production rigs as well, possibly with a slightly reduced set of available features (e.g. auto-band switching if the rig can't provide the required data). The KPA800/1500 CAN decode both serial AND voltage differential data from most current production rigs, so you can actually have two DIFFERENT rigs connected at the same time and still control the amp with EITHER rig. That feature alone, will make the amp quite desirable. 73, Tom Hammond N0SS At 10:48 AM 5/22/2006, [hidden email] wrote: >The reasons amps seem expensive: > >1) They use expensive parts if bought new. Manufacturers >can't/won't/don't use surplus, so they have to pay >full price for everything. > >2) Many of the parts are expensive because they're custom and/or low >quantity items. > >3) The market is relatively limited, so the engineering and tooling >costs have to be amortized over fewer units. >Elecraft has sold less than 6000 K2s since the rig was introduced in >1999. As good as the Elecraft amps >obviously are, and as much as many of us want one, how many units >can they reasonably expect to sell in the >next 7 years? > >73 de Jim, N2EY > >-----Original Message----- >From: michael taylor <[hidden email]> >To: [hidden email] >Sent: Mon, 22 May 2006 11:23:57 -0400 >Subject: Re: [Elecraft] QRO > > >I'm curious, what makes RF amplifiers fairly expensive projects? I >admit I have no experience or exposure to them, but as far as I can >tell the two major building blocks are a power supply and a not >terribly complex amplifier circuit. > >Is the bulk of the cost in the amp device(s) - power transistors or >vacuum tubes/values? > > > >_______________________________________________ >Elecraft mailing list >Post to: [hidden email] >You must be a subscriber to post to the list. >Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > >Help: http://mailman.qth.net/subscribers.htm >Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by Ed Lambert
This means more power splitters and combiners!
Can someone please tell us exactly which mosfets are used in the KPA800? On May 22, 2006, at 11:00 AM, Ed Lambert wrote: > > > The big amp uses 16 FET's (not Motorola but I can't remember which > ones) _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by Tom Hammond-3
>tom said: >you can actually have two DIFFERENT rigs connected at the same time >and still control the amp with EITHER rig.,,,,,, I had not yet thought that thru,,, Since the amp take 2 rigs, elecraft was wise to figure the other radio might not be a K2 !!!!!!! COOL...... good to see ya Tom, bill ny9h _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Non-K2 owners - take note:
It is not even necessary to have one K2 to drive the Elecraft amp. Of course, many would also like to have the K2 as one or both transcivers. Don W3FPR -----Original Message----- I had not yet thought that thru,,, Since the amp take 2 rigs, elecraft was wise to figure the other radio might not be a K2 !!!!!!! COOL...... -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.392 / Virus Database: 268.6.1/344 - Release Date: 5/19/2006 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by Vic K2VCO
Ten Tec also sells ready made enclosures, steel or aluminum :
http://www.tentec.com/ Rich k2cpe K2 #1102 ----------------------------------------------------------------------------------- > Brian F. Wruble wrote: > >> I have always wanted to try building one of those big amplifiers. >> One thing >> that stops me is that I have no idea where you get or how you build >> all the >> "sheet metal" parts --- complicated pieces of chassis, etc. Anybody out >> there who knows how people manage to build or source these? > > > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by Ed Lambert
Isn't "conventional wisdom" that tube-based amplifiers are inherently
more rugged and forgiving that transistor amplifiers, easier to work on or repair in the field, and that tube amps are the "way to go?" Has that changed, and other than price alone, why should I consider the new Elecraft amp over a tube design featuring auto tuning such as the Acom or the Alpha (older 87A or the new 9500)? Lou, W0FK "Vic, K2VCO wrote: Tube amplifiers are expensive because high power components (HV variable capacitors, high power bandswitches, power transformers, tubes, sockets, etc.) are expensive. In addition, although the basic circuit is quite simple, ancillary circuits to protect the expensive parts and provide functionality like QSK and automatic tuning are needed. Finally, the enclosure is large and must be well-constructed to be RF tight. A homebrewer can build an amplifier relatively cheaply by using surplus Russian tubes and scrounging parts. But you need to know what you're doing, since mistakes can be fatal. Transistor amplifiers are expensive because they are more complex. A KW amplifier may have 8 power transistors, and the protective circuitry may be more complicated than that for a tube amplifier. If you know that you will be driving a 50 ohm load, automatic tuning is simple; just switch in the appropriate lowpass filter for each band. However, transistor amps are unhappy with even a low-to-moderate SWR, so a built-in antenna tuner is really needed. -- 73, Vic, K2VCO Fresno CA" _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
St. Louis, MO
"The difference between stupidity and genius is that genius has its limits." Albert Einstein |
At 04:19 PM 5/22/2006, Lou Laderman wrote:
>and other than price alone, why should I consider the >new Elecraft amp over a tube design featuring auto tuning such as the >Acom or the Alpha (older 87A or the new 9500)? 1. the auto tune in the kpa 800/1500 will be faster, since there are no inductors that "roll".... 2. it will weigh A LOT LESS,, if that parameter is of concern,,,,,(dxpeditions) 3. since you have the option of final assembly, you SHOULD have a much better handle on the "goings on" inside,,,, thus increasing your odds of a local repair. 4. I believe that the rs-232 port will enable a firmware update. I don't believe that is available for the "A" amps. 5. an internet full of assistants to help you 24/7.....other "builder/assemblers" however I don't believe that ACOMs have had any major spills, and what they had was handled quickly by the east coast guys.... 6 and as you suggested I think the full bore box ( KPA-1500) IS less money than the ALPHA or ACOM 2000A....of which only the ACOM is shipping and has been proven a great product .... 7. looks like the 9500 is avoiding some of the 87A issues by opting for vacuum relay, not the diodes that Eric/Wayne have chosen. However IF you like a "light show" the ALPHA WINS BIGTIME....... with certainly more stuff than the eye can absorb...( i like that junk!!) The ALPHA has 4 antenna jacks, but I don't see that it's set up already for SO2R....maybe so,,,,The KPA-800/1500 IS SO2R. And Elecraft won't take any of your money to "put you in line" for a new amp. DAYTON WAS A BLAST,,,, bill ny9h _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by W0FK
At 02:19 PM 5/22/2006, Lou Laderman wrote:
>Isn't "conventional wisdom" that tube-based amplifiers are inherently >more rugged and forgiving that transistor amplifiers, easier to work on >or repair in the field, and that tube amps are the "way to go?" >Has that changed, and other than price alone, why should I consider the >new Elecraft amp over a tube design featuring auto tuning such as the >Acom or the Alpha (older 87A or the new 9500)? >Lou, W0FK Well, first off the KPA amps have auto-tuning with a built-in antenna tuner, based on the KAT100 design - with a little less SWR latitude than the KAT100. Second, there is circuitry to prevent damage to the transistor finals. Lastly and most interesting - this was something Eric showed me last year, and he can chime in if it has changed - but they have designed the amps based on two-transistor modules that are easily field replaced. I think packing extra PCBs will be easier for a DXpedition than packing extra tubes. Elecraft was also planning to 'loan' these spares to DXpeditions - if they aren't used, you don't pay for them. - jeff wk6i -- Jeff Stai [hidden email] Twisted Oak Winery http://www.twistedoak.com/ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by W0FK
Antenna tuning in addition to auto tuning is a very desirable feature for
me. The Elecraft amps include antenna tuning in addition to auto tuning. Alpha says they are working on an antenna tuner. So, add the cost of that unit to the $9100.00. Of course, tube amplifiers are maybe not as sensitive to antenna match but at these voltages and currents... Ed Lambert, KD3Y > ...new Elecraft amp over a tube design featuring auto tuning such as the > Acom or the Alpha (older 87A or the new 9500)? > Lou, W0FK _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by Ed Lambert
True, but the Elecraft will only match 3:1 at 1500 watts, not a lot of
room. Lou -----Original Message----- From: Ed Lambert [mailto:[hidden email]] Sent: Monday, May 22, 2006 5:11 PM To: [hidden email]; [hidden email] Subject: RE: [Elecraft] QRO Antenna tuning in addition to auto tuning is a very desirable feature for me. The Elecraft amps include antenna tuning in addition to auto tuning. Alpha says they are working on an antenna tuner. So, add the cost of that unit to the $9100.00. Of course, tube amplifiers are maybe not as sensitive to antenna match but at these voltages and currents... Ed Lambert, KD3Y > ...new Elecraft amp over a tube design featuring auto tuning such as > the Acom or the Alpha (older 87A or the new 9500)? Lou, W0FK _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
St. Louis, MO
"The difference between stupidity and genius is that genius has its limits." Albert Einstein |
In reply to this post by Ed Lambert
One of the Alpha customers allegedly burned down his house by performing a
"stupid antenna trick". (Unmatched antenna in unfortunate proximity to his deck) Ed Lambert KD3Y > ...but at these voltages and currents... _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
In reply to this post by Ed Lambert
Lou wrote:
"...but the Elecraft will only match 3:1 at 1500 watts, not a lot of room." ========== It means a lot when you consider that the Alpha and Acom amps fault at 2:1. 73, de Earl, K6SE _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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